Global positioning system (GPS) devices are commonly used to facilitate navigation on Earth. These GPS devices are designed to communicate with orbiting satellites that transmit location and time information. Closer to the Earth's surface, such satellite-based navigation can be supplemented using local area wireless technologies, such as Wi-Fi, which utilize radio frequency (RF) signals to communicate with nearby compatible devices. These types of wireless technologies typically employ wireless access points (Wi-Fi hotspots) to establish network access. GPS and Wi-Fi systems, alone or in combination, can be used to provide navigational instructions to a user in possession of a receiver configured for decoding one or more of these types of signals.
However, GPS and Wi-Fi signals are not adequate in all situations. In some cases, GPS and Wi-Fi signals are not precise or accurate enough. In other cases, a user may be in a location where the signals are absent. For example, the concrete and metal structure of a parking garage may attenuate GPS and Wi-Fi signals, leaving the receiver of the user without processable location or navigational signals. In these cases, an alternative or supplemental technology would be helpful for providing location and navigational information to a user.
The figures depict various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein.